Re: THE LOOK.
Adora was there with Catra, dressed like a lady greaser, essentially. She did not sing because that would be, uh, bad and she doesn't want to hurt anyone's ears. She cheered for anyone who did sing, though, and probably nursed just a beer for the night because, tragically, she's a terrible lightweight.
Alex was there with Kara and Lena, dressed like this as a result of going to check on Lena (she was fine until then, damn it). She definitely dueted with Kara but no solo performances.
Waverly was there with Nicole and the rest of the fam if they decided to come! She was dressed in matching outfits with Nicole (hers is the dress and tall boots). She sang a couple of times and insisted on dueting with her beautiful wife and eye-sexing her.